In the file folder suspension systems most commonly in use, tools are required to assemble (or disassemble) the parts. For example, FIG. 1 depicts a conventional assembly 10 in which a pair of side rails 11 are supported at each of their ends by an end frame 12. Each end frame includes a lower portion with upstanding arms 12a and a spreader bar 12b, and screws 13 extend through threaded openings of the two parts to clamp the ends of the rails 11 in the manner shown in the drawing. While such a construction is effective and relatively inexpensive, its assembly and diassembly require the use of tools such as a screwdriver and/or wrench. Economy is therefore achieved at the cost of inconvenience.
Systems are known in which end frames and rails may be assembled without the use of tools. In U.S. Pat. No. 4,176,753, end frames are U-shaped in configuration and plastic corner fittings 22 are secured to the upstanding side bars of those frames. Side rails may be snapped into position between the jaws of the corner fittings and spreader tubes then inserted into openings in the back wall of each fitting to engage bosses provided by those fittings.
While such a system eliminates screws and the need for tools, it is relatively expensive to manufacture, especially if the molded (or cast) corner fittings must be pre-assembled with the end frames during such manufacture. Also, the attachment between the corner fittings and the upright bars and spreader tubes may present problems since no tightening of the connections between the parts occurs during or following assembly. Should upward forces, or lateral forces, be exerted on the side rails following assembly, such fittings might become disengaged from the bars of the end frames or from the horizontal spreader tubes.
Accordingly, it is an object of this invention to provide a system that eliminates the use of screws and tools but is self-tightening in operation so that problems of inadvertent disassembly in later use are avoided or greatly reduced. It is also an object to provide a system that is relatively inexpensive and to manufacture and which requires no pre-assembly of parts.
In brief, the assembly utilizes spring metal clips at each of its four corners for securely holding together the side rails and the upstanding side bars of the end frames of that assembly. Each clip is generally S-shaped in configuration and may be inexpensively stamped from spring metal stock. The intermediate and base portions of each S-shaped clip have aligned openings for receiving an upper end of a side bar of an end frame. Subsequent insertion of the end of a file-suspension rail between the intermediate and lower portions of a clip causes those portions to flex away from each other and tightly grip both the rail and the upper end of the side bar that projects through the aligned openings.
The spring clips are also provided with openings for receiving the ends of spreader bars which engage the upper ends of the upstanding side bars and which complete the end frame assembly at each end of the structure. The top portion of each S-shaped clip extends over the contacting ends of the spreader and side bars to conceal such portions and also engages the side bars to insure against any possibility of the clips shifting downwardly along those side bars when the structure is in use.
To retain the side rails in place, each clip has its base portion provided with an upstanding flange and its intermediate portion with a depending projection. The upper edge of each rail is wedged tightly between the projection and the upper end of a side bar extending through the aligned openings of the clip and, ideally, the parts are constructed and arranged so that the side rail slopes upwardly and inwardly into tight wedging contact with the side bar.
Other features, advantages, and objects will become apparent from the specification and drawings.